nl80211: clarify comment for mesh PLINK_BLOCKED state

When a mesh link is in blocked state, it is very useful to still allow
auth requests from the peer to re-establish it.
When a remote node is power cycled, the peer state can easily end up
in blocked state if multiple auth attempts are performed. Since this
can lead to several minutes of downtime, we should accept auth attempts
of the peer after it has come back.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20211220105147.88625-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>